Apparatus for developing an anatomic space for laparoscopic hernia repair and patch for use therewith

ABSTRACT

An apparatus for creating an anatomic space in tissue in a body includes an introducer device having a tubular member with a bore extending therethrough. A tunneling shaft assembly is slidably mounted in the bore of the introducer device. The tunneling shaft assembly includes a tunneling shaft having proximal and distal extremities. A blunt tip is secured to the distal extremity of the tunneling shaft. A balloon assembly is provided. The balloon assembly is removably secured to the tunneling shaft. The balloon assembly includes a deflated collapsed balloon. A sheath encloses the balloon and is carried by the tunneling shaft. The sheath has a weakened region extending longitudinally thereof permitting the sheath to be removed to release the balloon.

This is a divisional of pending U.S. application Ser. No. 08/124,283filed on Sep. 20, 1993, which is a continuation-in-part of pending U.S.application Ser. No. 07/893,988 filed on Jun. 2, 1992.

This invention relates to an apparatus and method for developing ananatomic space for laparoscopic hernia repair and a patch for usetherewith.

In the past, in developing spaces and potential spaces within a body,blunt dissectors or soft-tipped dissectors have been utilized to createa dissected space which is parallel to the plane in which the dissectorsare introduced into the body tissue. This often may be in an undesiredplane, which can lead to bleeding which may obscure the field and makeit difficult to identify the body structures. In utilizing suchapparatus and methods, attempts have been made to develop anatomicspaces in the anterior, posterior or lateral to the peritoneum. The sameis true for pleural spaces and other anatomic spaces. Procedures thathave been performed in such spaces include varicocele dissection, lymphnode dissection, sympathectomy and hernia repair. In the past, theinguinal hernia repair has principally been accomplished by the use ofan open procedure which involves an incision in the groin to expose thedefect in the inguinal floor, remove the hernial sac and subsequentlysuture the ligaments and fascias together to reinforce the weakness inthe abdominal wall. Recently, laparoscopic hernia repairs have beenattempted by inserting laparoscopic instruments into the abdominalcavity through the peritoneum and then placing a mesh to cover thehernia defect. Hernia repair using this procedure has a number ofdisadvantages, principally because the mesh used for hernia repair is indirect contact with the structures in the abdominal cavity, as forexample the intestines, so that there is a tendency for adhesions toform in between these structures. Such adhesions are known to beresponsible for certain occasionally serious complications. Such aprocedure is also undesirable because typically the patch is stapledinto the peritoneum, which is a very thin unstable layer covering theinner abdomen. Thus, the stapled patch can tear away from the peritoneumor shift its position. Other laparoscopic approaches involve cuttingaway the peritoneum and stapling it closed. This is time consuming andinvolves the risk of inadvertent cutting of important anatomicstructures. In addition, such a procedure is undesirable because itrequires the use of a general anesthesia. There is therefore a need fora new and improved apparatus and method for developing an anatomic spaceand particularly for accomplishing hernia repair by laparoscopy.

In general, it is an object of the present invention to provide anapparatus and method for developing an anatomic space.

Another object of the invention is to provide an apparatus and method inwhich such an anatomic space is developed by applying perpendicularforces to create the anatomic space at the weakest plane to create amore natural, less traumatic and bloodless region in which to work.

Another object of the invention is to provide an apparatus and method toobtain surgical exposure in the preperitoneal space.

Another object of the invention is to provide an apparatus and method tocreate an extraperitoneal working space utilizing a balloon dissector.

Another object of the present invention is to provide an apparatus andmethod of the above character for developing an anatomic space forlaparoscopic hernia repair through the anatomic space.

Another object of the invention is to provide an apparatus and methodfor decreasing the time and risk associated with creating apreperitoneal working space.

Another object of the present invention is to provide an apparatus andmethod of the above character for developing an anatomic space forlaparoscopic hernia repair through the anatomic space.

Another object of the invention is to provide an apparatus and method ofthe above character which requires a minimally invasive procedure.

Another object of the invention is to provide an apparatus and method ofthe above character which can be accomplished without the use of ageneral anesthesia.

Another object of the invention is to provide an apparatus and method ofthe above character which can be accomplished with a spinal or epiduralanesthesia.

Another object of the invention is to provide an apparatus and method ofthe above character which provides substantially reduced medical costsand a greatly reduced patient recovery time.

Another object of the invention is to provide an apparatus of the abovecharacter which is relatively simple and compact.

Another object of the invention is to provide an apparatus and method ofthe above character which can be readily utilized by surgeons.

Another object of the invention is to provide a patch for use in theapparatus which is firmly secured during the hernia repair.

Another object of the invention is to provide a balloon which has amodified asymmetric manta ray configuration to aid in providing thedesired configuration for the extraperitoneal working space for herniarepair.

Another object of the invention is to provide a balloon dissectionapparatus in which the balloon cover is detachably secured to theobturator so that the balloon dissection device is relatively rigid topermit the balloon dissection apparatus to be grasped by the handle tooperate the same during dissection.

Another object of the invention is to provide a balloon dissectionapparatus of the above character in which a precise release mechanism isprovided for releasing the balloon cover from the obturator so that thesurgeon can be assured that the balloon cover has been released beforeit is removed to release the balloon.

Another object of the invention is to provide a balloon. dissectionapparatus of the above character in which the guide rod or obturatorremain in place to maintain ready access to the extraperitoneal workingspace.

Another object of the invention is to provide a balloon dissectionapparatus of the above character in which certain of the parts which areto be moved relative to other parts are color coded to aid the surgeonin use of the apparatus.

Another object of the apparatus is to provide an introducer member whichis provided with a tip having an inclined surface.

Another object of the invention is to provide a balloon dissectionapparatus which is provided with a blunt tip which has a diameter whichis less than the diameter of the cannula tube.

Another object of the invention is to provide a balloon dissectionapparatus of the above character in which at least a part of the samecan be sterilized and reused.

Additional objects and features of the invention will appear from thefollowing description in which the preferred embodiments are set forthin detail in conjunction with the accompanying drawings.

FIG. 1 is a side elevational view partially in cross-section of alaparoscopic apparatus incorporating the present invention.

FIG. 2 is a cross-sectional view taken along the 2--2 of FIG. 1.

FIG. 3 is a side elevational view partially in cross-section of thetunneling shaft forming a part of the apparatus shown in FIG. 1 after ithas been removed from the apparatus shown in FIG. 1.

FIG. 4 is a cross-sectional view taken along the line 4--4 of FIG. 3.

FIG. 5 is an isometric view of the inflatable balloon utilized in theapparatus in FIG. 1 secured to the tunneling rod.

FIG. 6 is a cross-sectional view taken along the line. 6--6 of FIG. 5,and showing by dotted lines the manner in which the balloon as itunfolds develops the anatomic space.

FIG. 7 is a partial plan view of a prone human body, showing the lowerabdomen showing the manner in which the laparoscopic apparatus of thepresent invention is utilized for performing a hernia repair through thepreperitoneal space.

FIG. 8 is a sagittal view of the lower abdominal cavity of the humanbeing shown in FIG. 7 showing the apparatus of the present inventionintroduced into the preperitoneal space.

FIG. 9 is a view similar to FIG. 8 but showing the sleeve removed fromthe apparatus and with the balloon inflated.

FIG. 10 is a sagittal view similar to FIG. 8 showing the balloondeflated and being removed.

FIG. 11 is a sagittal view similar to FIG. 8 showing removal of thetunnelling shaft.

FIG. 12 is an isometric view of a patch incorporating the presentinvention.

FIG. 13 is a side elevational view of the patch shown in FIG. 12.

FIG. 14 is an isometric view showing the patch in FIGS. 12 and 13 in arolled-up, generally cylindrical configuration.

FIG. 15 is a sagittal view showing the hernia sac of hernia that is tobe repaired.

FIG. 16 is a sagittal view showing the introducer through which therolled-up patch in FIG. 17 has been introduced into the preperitonealspace by an introducer rod.

FIG. 17 is a sagittal view similar to FIG. 16 showing the attachment ofthe patch to the hernia sac.

FIG. 18 is a sagittal view similar to FIG. 17 showing the dissection ofthe hernia sac and the unrolling of the patch.

FIG. 19 is a sagittal view showing the patch in place to provide thehernia repair.

FIG. 20 is an isometric view of another embodiment of a balloon with apatch disposed thereon for use with the apparatus of the presentinvention.

FIG. 21 is a cross-sectional view taken along the line 21--21 of FIG.20.

FIG. 22 is an enlarged cross-sectional view taken along the line 22--22of FIG. 23.

FIG. 23 is a sagittal view showing the manner in which the balloon andpatch shown in FIG. 20 are disposed in the preperitoneal space.

FIG. 24 is a sagittal view showing the placement of the balloon and thepatch of FIG. 20, and the inflation of the balloon in the preperitonealspace.

FIG. 25 is an isometric view of another embodiment of a balloon andpatch for use with the apparatus of the present invention.

FIG. 26 is a rolled-up cross-sectional view of the balloon and patchshown in FIG. 25.

FIG. 27 is an isometric view of another embodiment of a patch for usewith the apparatus of the present invention.

FIG. 28 is an isometric view of the patch shown in FIG. 27 wrapped in anintroducer assembly.

FIG. 29 is a top plan view of another embodiment of a laparoscopicapparatus incorporating the present invention.

FIG. 30 is a side elevational view taken along the line 30--30 of FIG.29.

FIG. 31 is a cross-sectional view taken along the line 31--31 of FIG.30.

FIG. 32 is a cross-sectional view taken along the line 32--32 of FIG.30.

FIG. 33 is an enlarged cross-sectional view of the distal extremity ofthe laparoscopic apparatus shown in FIG. 29.

FIG. 34 is a partial plan view showing the balloon after it has beenremoved from the laparoscopic apparatus with the obturator tip shiftingits position.

FIG. 35 is a plan view of the balloon shown in FIG. 34 as it is beingremoved from the body of the patient and bringing along with it theobturator tip.

FIG. 36 is a side elevational view of another embodiment of alaparoscopic apparatus incorporating the present invention.

FIG. 37 is a plan view showing the balloon from the apparatus shown inFIG. 36 in an inflated condition and showing the tunneling rod mountedtherein being prevented from being advanced beyond the distal extremityof the balloon.

FIG. 38 is a plan view showing the manner in which the balloon isseparated from the tunneling rod as it is retracted.

FIG. 39 is an isometric view of a surgical dissector with a cannulaincorporating the present invention in an assembled condition.

FIG. 40 is an isometric exploded view of the components of the surgicaldissector with cannula shown in FIG. 39.

FIG. 41 is a side elevational view of the assembly shown in FIG. 39.

FIG. 42 is a top plan view looking along the line 42--42 of FIG. 41.

FIG. 43 is a view partly in cross section taken along the line 43--43 ofFIG. 42.

FIG. 44 is a view looking along the line 44--44 of FIG. 41.

FIG. 45 is a partial side elevational view of the assembly shown in FIG.1 with the clamping mechanism moved to a release position.

FIG. 46 is a view taken along the line 46--46 of FIG. 45.

FIG. 47 is a partial side elevational view of an assembly shown in FIG.41 with the retaining ring moved to a locked position.

FIG. 48 is a cross-sectional view taken along the line 48--48 of FIG.47.

FIGS. 49A-49G are views showing use of the surgical dissector shown inFIG. 1 in a laparoscopic hernia procedure.

FIG. 50 is a cross-sectional view taken along the line 50--50 of FIG.49C.

FIG. 51 is a cross-sectional view taken along the line 51--51 of FIG. 52showing another embodiment of a balloon dissection apparatusincorporating the present invention.

FIG. 52 is an end elevational view taken along the line 52--52 of FIG.51.

FIG. 53 is an enlarged cross-sectional view taken along the line 53--53of FIG. 51.

FIG. 54 is an enlarged cross-sectional view taken along the line 54--54of FIG. 53.

FIG. 55 is an enlarged cross-sectional view of a portion of the viewshown in FIG. 51 showing the latch members moved to permit removal ofthe guide rod.

In general, the apparatus of the present invention is used for insertioninto a body to create an anatomic space. The apparatus is comprised of atubular introducer member having a bore extending therethrough. Atunneling shaft is slidably mounted in the bore and has proximal anddistal extremities including a bullet-shaped tip. A rounded tunnelingmember is mounted on the distal extremity of the tunneling shaft. Aninflatable balloon is provided. Means is provided on the balloon forremovably securing the balloon to the tunneling shaft. Means is alsoprovided for forming a balloon inflation lumen for inflating theballoon. The balloon is wrapped on the tunneling shaft. A sleevesubstantially encloses the balloon and is carried by the tunnelingshaft. The sleeve is provided with a weakened region extendinglongitudinally thereof, permitting the sleeve to be removed whereby theballoon can be unwrapped and inflated so that it lies generally in aplane. The balloon as it is being inflated creates forces generallyperpendicular to the plane of the balloon to cause pulling apart of thetissue along a natural plane to provide the anatomic space.

More in particular, as shown in the drawings, the apparatus or device 31for creating such an anatomic space for use in a laparoscopic procedure(see FIG. 1) includes an introducer sleeve or device 32 which consistsof a tubular member 33 formed of a suitable material such as plasticwhich is provided with a bore 34 extending throughout the lengththereof. A handle section 36 is mounted on one end of the tubular member33 and is also formed of a suitable material such as plastic. It isprovided with a bore 37 which is in communication with the bore 33. Aflapper valve 38 is mounted within the section 36 and is movable betweena position in which it closes off the bore 37 and position out of theway of the bore 37, by means of a finger operated actuator 39 mounted onthe exterior of the section 36. A stopcock 41 is mounted on the section36 and is in communication with the passage 37. A lever 42 is providedfor opening and closing the stopcock

A tunneling shaft assembly 46 is slidably mounted in the bores 37 and 34of the introducer sleeve 32. The tunneling shaft assembly 46 consists ofa tunneling shaft or rod 47 formed of a suitable material such asstainless steel, of a suitable length, as for example 18 inches, and asuitable diameter of approximately 1/8 inch. The tunneling rod 47 isprovided with proximal and distal extremities 48 and 49.

An introducer member 51 is slidably mounted on the tunneling shaft orrod 47 and is formed of a suitable material such as plastic. Theintroducer member 51 is substantially hollow as shown and is providedwith a bore 52 through which the tunneling shaft 47 extends. The.introducer member 51 is provided with a substantially hemispherical tip53 to form a rounded protrusion or first obturator through which the rod47 extends. The introducer member 51 has a length such that when it isintroduced into the bore 34 of the introducer sleeve, it extends out ofthe distal extremity of the introducer sleeve 32, as shown particularlyin FIG. 1. This diameter of the introducer member 51 is sized so that itcan be slidably mounted in the bore 34. The other end of the introducermember 51 is provided with a chamfer 54.

A disk-type seal 43 having a central opening is provided in the section36 in alignment with the bore 37, and is adapted to permit theintroduction of the introducer member 51 therethrough.

The section 36 forms one part of a three-piece handle 56 of thelaparoscopic apparatus 31 which is sized so that it is adapted to begrasped by the human hand. As can be seen particularly in FIG. 4, thehandle 56 is generally rectangular in cross-section. The handle 56 isprovided with an intermediate section 57 which has a bore 58 extendingtherethrough in registration with the bore 37 and has the same generaldiameter as the bore 37 so that the introducer member 51 can traveltherethrough. The sections of the handle 56 can be characterized ashaving first, second and third sections, in which section 36 is thefirst section and intermediate section 57 is the second section.Latching means is provided for interconnecting the intermediate section57 to the end section 36, and consists of a pair of oppositely disposedlatches 61 pivotally mounted on the pins 62 in the intermediate section57. Each of the latches 61 is provided with a latch portion 63 adaptedto engage a protrusion 64 provided on the end section 36, and isyieldably urged into engagement therewith by a spring 66. Each of thelatches is provided with a cam surface 67 which is adapted to be engagedby the chamfer 54 of the introducer member 51 to cam the latch portion63 out of engagement with the protrusion 64 to release the intermediatesection 57 from the end section 36 for a purpose hereinafter described.

The handle 56 also consists of another end section 71, which can also becharacterized as the third section, which is secured to the proximalextremity of the tunneling shaft or rod 47. A pair of latches 72 areprovided in the end section 71 and are pivotally mounted on pins 73. Thelatches 72 are provided with latch portions 74 adapted to engageprojections 76 provided in the intermediate section 57. Means isprovided for yieldably retaining the latches 72 in engagement with theprojections 76 and consists of a U-shaped spring 77 mounted within theend section 71 and engaging the latches 72. The latches 72 are providedwith knurled portions 72a which extend outwardly which are adapted to begrasped by the fingers of the hand so that the latch portions 74 can bemoved out of engagement with the projections 76 against the force of thespring 77.

The tunneling shaft assembly 46 also includes a tunneling member or tip79 which is mounted on the distal extremity of the tunneling shaft orrod 47. As shown, the tip 79 is substantially olive-shaped and can alsobe called a second obturator. It is provided with a roundedhemispherical surface on its distal extremity which has a maximumdiameter which is slightly less than the diameter of the bores 34 and 37so that it can pass through the introducer sleeve 32. The proximalextremity of the tip 79 is of smaller diameter to provide an annularstep 81 in the tip. The proximal extremity of the tip 79 is alsohemispherical, as shown. The tunneling member or tip 79 can be formed ofa suitable material such as plastic and can be secured to the distalextremity of the tunneling shaft or rod 47 by suitable means such as anadhesive. As hereinafter explained, the tunneling shaft or guide rod 47is movable so that the tip 79 can be brought into engagement with thehemispherical end 53 of the introducer member 51 for a purposehereinafter described.

The laparoscopic apparatus 31 also includes a balloon assembly 86 whichis shown in FIGS. 2, 5 and 6. As shown in FIG. 5, when the balloonassembly 86 consists of a balloon 87 which in plan, when deflated, has apear-shaped configuration. The balloon is preferably formed of anon-elastomeric, medical-grade material of a suitable type such as PVC.Thus, the balloon 87 can be formed of two sheets 88 and 89 of such amaterial which have their outer margins bonded together by suitablemeans such as by a heat seal 91 extending around the perimeter of theflat balloon 87. The balloon 87 is provided with a neck 94 into which aflexible tubular member 96 extends, and is secured therein in a suitableairtight fashion such as by an adhesive. The tubular member 96 isprovided with a lumen 97 which is in communication with the interior ofthe balloon and which can be used for inflating the balloon through aLuer-type fitting 98 mounted on the free end of the tubular member 96.

Means is provided for removably securing the balloon 87 to the tunnelingrod or shaft 47, and consists of a sleeve 101 formed of the samematerial as the balloon 87, and which can be formed integral or separatetherefrom and adhered thereto by suitable means such as an adhesive. Thesleeve 101 extends longitudinally of the balloon 87 and is disposedgenerally equidistant from the side margins of the same. The sleeve 101is provided with a passage 102 extending therethrough which is sized toslidably accommodate the tunneling shaft or rod 47. Means is providedfor permitting separation of the balloon 87 from the tunneling rod bymovement sidewise from the axis of the passage 102 and takes the form oflongitudinally spaced apart perforations 103 in the sleeve 101 extendinglongitudinally the length of the sleeve 101. The perforations 103 arespaced close enough together to form a weakened region so that theballoon can be readily separated from the tunneling rod by separatingthe plastic sleeve 101 by tearing the plastic between the perforationsas hereinafter described.

As shown in FIG. 6, the sleeve 101 is disposed equidistant from the sidemargins of the balloon, permitting the balloon to be inflated ashereinafter described and as also shown by the dotted lines in FIG. 6,to be inflated around the rod 47. When deflated, the side margins of theballoon 87 can be rolled inwardly toward the rod 47 as shown by thebroken lines in FIG. 6 to permit the same to be folded into a generallycylindrical configuration as shown in FIG. 2, and to be enclosed withina removable sleeve 106 carried by the tunneling shaft or rod 47. Theremovable sleeve 106 is formed of a relatively thin-walled tubularmember 107 of a suitable material such as Teflon which has a weakenedregion 108 in its wall extending longitudinally the length thereof. Thisweakened region 108 can take the form of a slit as shown, or can be aseries of perforations or slots formed in the wall, or a combinationthereof. The proximal extremity of the tubular member 107 is providedwith split-apart or separable end portions 107a and 107b to which aresecured finger rings 109 of a suitable material such as plastic andsecured thereto by fasteners 111.

Operation and use of the laparoscopic apparatus in performing the methodfor laparoscopic hernia repair through preperitoneal space may now bebriefly described as follows. Let it be assumed that the laparoscopicapparatus 31 has been assembled as shown in FIG. 1. As shown in FIG. 7,let it be assumed that a human patient 121 is in a prone position andhas a hernia 122 in the lower abdominal area which he wishes to haverepaired. The patient is prepared in an appropriate manner byadministering a suitable anesthesia, as for example a spinal anesthesia,and any other necessary preparation. The surgeon first makes aninfraumbilical incision 126 in the skin below the navel or umbilicus 127and separates the fat 129 and then incises the anterior rectus sheath orfascia 131 in the midline. Care should be taken not to penetrate theperitoneum overlying the abdominal cavity 133 (see FIG. 8).

After the incision 126 has been made in the manner hereinbeforedescribed, the laparoscopic apparatus 31 is then taken by one hand ofthe surgeon, grasping the handle 56 and utilizing the other hand tofacilitate the insertion of the rounded blunt tip 79 into the incision126. The blunt tip 79 is caused to enter the slit in the fascia 131 andpass anterior to the peritoneum 132, in between the rectus muscles(laterally), and enters the potential preperitoneal space 136 to beprovided for the laparoscopic procedure. The blunt tip 79 is thenutilized as a tunneling device by the surgeon using one hand 56 toadvance the blunt end 79 toward the pubic region of the patient whilethe surgeon places his other hand on the abdomen to feel the apparatusor device 31 as it is being advanced. The advance of the device 31 iscontinued until the blunt tip 79 is below the symphysis pubis 137 asshown in FIG. 8, and preferably is disposed between the symphysis pubis137 and the bladder 138.

After the apparatus or device 31 has been properly positioned as shownin FIG. 8, the removable sleeve or sheath 106 is removed by the surgeonusing one hand to engage the finger rings 109 which are exterior of thebody of the patient and outside of the incision 126. At the same time,the other hand of the surgeon is utilized to stabilize the portion ofthe device 31 which is within the preperitoneal space. The sheath 106can be readily withdrawn since it is formed of Teflon and is split orweakened along its length, by pulling it proximally and away from thelongitudinal axis of the tubular member 33. As the sheath 106 opens andslips off, it exposes the balloon 87 of the balloon assembly 86. Whenthe sheath 106 is completely removed, a sterile saline solution servingas a balloon inflation medium is introduced into the balloon 87 throughthe tubular member 96 by connecting a conventional syringe 141 to theLuer fitting 98. The balloon 87 typically can be inflated to a suitablesize by introducing 500 cc or less of normal saline solution into theballoon by pressing on the plunger 142. As the balloon 87 is inflated,the balloon progressively unwraps with its side margins rollingoutwardly from the center while expanding into a plane to causeprogressive separation or dissection of tissue (i.e. 131, 132) along itsweakest points by application of forces generally perpendicular to theplane of the balloon as indicated by the arrows 143 in FIGS. 6 and 9, tocreate the preperitoneal or anatomic space. The balloon 87 expandsaround the tunneling shaft 47 in the manner shown in broken lines inFIG. 6 to achieve the progressive separation until complete inflation isachieved. The surgeon can sense the filling of the balloon by feelingthe abdomen of the patient as the balloon is inflated. The balloon 87serves to open up the preperitoneal space 136 to provide a bloodlessspace for the procedures hereinafter to be performed. Since the balloonis formed of a non-elastomeric material, it is a volume-limited balloonto prevent overexpansion. Different sizes of balloons can be utilizedfor different patient sizes. With a smaller balloon it is possible todeflate the balloon and then shift the balloon and again reinflate it toobtain the desired bloodless preperitoneal space.

After the desired bloodless anatomic space or pocket 136 is formed, theballoon 87 is deflated by withdrawing the normal saline solution bywithdrawal of the plunger 142 of the syringe 141 or via a hospitalvacuum aspirator. After the balloon 87 has been deflated, the balloonassembly 86 can be removed by grasping the handle 56 of the laparoscopicapparatus or device 31 with one hand and using the other hand to graspthe tubular member 96 and the proximal extremity of the balloon 87 andto remove the same through the incision 126, as shown in FIG. 10. As theballoon 87 is being removed, it is progressively separated from thetunneling rod or shaft 47 by causing the sleeve 101 to split apart alongthe longitudinal perforations 103 provided in the sleeve 101. This makesit possible to separate the balloon 87 from the tunneling rod 47 withoutthe necessity of removing the tunneling rod 47 or the introducer device32.

After the balloon assembly 86 has been removed, the introducer device 32can be advanced distally over the tunneling shaft or rod 47 so itextends well into the preperitoneal space 36 as shown in FIG. 11. Theend section 71 of the handle 56 is then removed by depressing thelatches 72 by having the fingers engage the portions 72a to disengagethe latch portions 74 from the intermediate section 57 of the handle 56.The end section 71 is then drawn proximally as shown in FIG. 11 to bringthe olive-shaped tip 79 into engagement with the obturator 53 disposedin the distal extremity of the tubular member 33 to cause both the tip79 and the obturator 53 to be withdrawn or retracted. As the introducermember 51 is being withdrawn, its chamfer 54 will strike the camsurfaces 67 of the latches 61 to cause them to disengage from the endpiece 36 to carry it along with the introducer member 51 and shown inFIG. 2. Thus, it can be seen that the tunneling shaft assembly 46 can bereadily removed merely by one motion of the surgeon's hand. Thereafter,a conventional laparoscope 144 (see FIG. 16) can be introduced throughthe introducer sleeve 32 to permit the surgeon to view the preperitonealspace 136.

The dissected preperitoneal space 136 is then insufflated with carbondioxide through the stopcock 41 to a pressure ranging from 6 to 8 mm ofmercury. Thereafter, two additional trocars 146 and 147 are introducedthrough the abdominal wall into the dissected preperitoneal space 136 inappropriate locations. Thus, as shown in FIG. 7, trocar 146 isintroduced into the left side of the abdomen of the patient below theintroducer sleeve 32 and the trocar 147 is introduced into the dissectedpreperitoneal space immediately above the symphysis pubis and directlybelow the introducer sleeve 32. As can be appreciated, the locations ofthe trocars 146 and 147 is generally dictated by the location of thehernia 122 to be repaired.

A patch 151 of the present invention to be utilized in the hernia repairprocedure is shown in detail in FIGS. 12, 13 and 14. The patch 151 canbe characterized as a hernia patch or graft and is made of a suitableplastic mesh such as a Prolene mesh manufactured by Ethicon, Inc. Thepatch 151 can be of any desired configuration. For example it can begenerally circular as shown, and consists of a disk 152 of a suitablediameter, as for example 2 inches. A tail 153 is secured to the disksubstantially in the center thereof, in a suitable manner. For example,as shown, the tail 153 can be provided with split portions 153a and 153bwhich are split apart and offset with respect to each other, which aresecured to a smaller reinforcing disk 154 formed of the same material asdisk 152 and secured to the disk 152 by suitable means such as surgicalthread (not shown). The tail 153 is formed of the same material as thedisk 152 and 154, or it can be formed of a different material, such asGoretex. It can have a size such that it has a width of approximately1/2 inch and a length of approximately 11/2 inches. As shownparticularly in FIG. 14, the side margins of the disk 152 can be rolledinwardly towards the center adjacent the tail 153 to form a cylindricalroll 156 such as shown in FIG. 14 with the tail 153 extending outwardlytherefrom. The roll 156 can be maintained in its rolled-up condition bymeans of sutures 157 disposed adjacent opposite ends of the roll and onopposite sides of the tail 153.

Conventional laparoscopic instruments are utilized which are introducedthrough the trocars 146 and 147 while visualizing the same through thelaparoscope 144 introduced through the introducer device 32 to dissectthe hernia 161 to permit visualization of its neck 162 as it is enteringthe internal inguinal ring 163. The hernia sac 161 is dissected from thesurrounding tissue (spermatic duct and vessels) (see FIG. 15). Theprocess is facilitated by CO₂ pressure impinging on the neck of thehernia sac. As soon as this dissection is completed, the roll 156 ispushed into the trocar 147 and advanced through the same by suitablemeans such as a deployment rod 164 (see FIG. 16) to enter the dissectedpreperitoneal space 13 as shown in FIG. 16. Alternatively, the roll 156can be placed in a tubular member (not shown) which can be used toposition the roll 156 within the trocar 157. Thereafter, by thedeployment rod 164, the roll 156 can be pushed out of the tubular memberinto the dissected preperitoneal space 136.

The roll 156 after it is in the preperitoneal space is then manipulatedso that its tail 153 is disposed alongside the neck 162 of the herniasac 161 as shown in FIG. 17. A conventional stapling device 166 is thenintroduced through the trocar 146 to staple the tail 153 to the neck 162by placing staples 167 therein. These staples 167 serve to divide theneck of the sac into distal and proximal portions 162a and 162b. As soonas this stapling operation is completed, the two portions 162a and 162bare separated from each other because of the pressure of theinsufflation gas to cause the tail 153 of the patch 151 to be pulledupwardly into the inguinal ring to pull with it the disk 152. Thesutures 157 are cut apart to permit the disk 152 to unroll and to beplaced across the inguinal ring 163 which created the main weakness inthe abdominal wall permitting the hernia which is being repaired tooccur. The proximal portion 162b of the neck 162 is stapled together bystaples 173 as shown in FIG. 18. The proximal portion 162 is thenpermitted to fold back into the desired anatomical location within theabdomen.

Thereafter, while observing the procedure under the laparoscope, thedissected preperitoneal space 136 can be deflated by permitting thecarbon dioxide gas to escape to the atmosphere through the stopcock 41in the introducer device 32 by operation of the stopcock lever arm 42.As deflation is taking place, the movement of the patch 151 is observedthrough the laparoscope 144 so that it does not become displaced. Whenthe deflation has been completed, the patch 151 is in a position overthe inguinal ring 163 and serves to provide enforcement to prevent theoccurrence of another hernia in that area. The tail 153 is disposed withthe inguinal ring 163 and retains the mesh disk 152 so that it surroundsthe inguinal ring 163.

After deflation has been accomplished, the trocars 146 and 147 as wellas the introducer device 32 can be removed. Small sutures can then beutilized to close the various small openings which have been provided inthe abdominal wall so that upon healing there will be minimal noticeablescars from the procedure. The scar in the navel or umbilicus typicallyis almost nearly invisible.

It has been found that the use of the laparoscopic apparatus 31 inaccomplishing the method as hereinbefore set forth provides a procedurein which the pain after the operation is markedly reduced. This isparticularly true since the operation does not involve suturing of anyligaments which typically produces the pain. In addition, the recoverytime for the patient is greatly accelerated. In the procedure of thepresent invention, a patient can return to work within a matter of 3 to5 days rather than in a number of weeks as in a conventional herniarepair procedure. The procedure also has other advantages. For example,there is a lack of necessity for a general anesthesia. Another principaladvantage of the procedure is there is no contact of mesh patch 151 withthe intestines of the patient or other intra-abdominal structures, thusgreatly reducing the possibility of adhesion formation. In addition, thegraft which is formed by the patch 151 is more secure and is positionedin an anatomically correct position. This is because the hernia sac isin exact alignment with the hernia and pulls with it the tail 153 of thegraft to ensure that the graft formed by the patch 151 is drawn into thecorrect position and is maintained in that position to preventmigration. In addition, the graft, by having an additional central disk154, ensures that additional reinforcement is provided in the properlocation in the center where the weakest region in the abdominal wallhas occurred. In addition, by such proper centering, the meshconstruction of the patch 151 serves to uniformly reinforce the areasurrounding the hernia.

Another embodiment of the present invention is shown in FIGS. 20, 21 and22 with respect to another embodiment of a balloon assembly 181 andanother embodiment of a patch or graft 182. The balloon assembly 181consists of a balloon 186 formed of two sheets 187 and 188 which arerectangular in shape, as for example square as shown in FIG. 20, whichare heat-sealed together at their outer margins as indicated by thebroken line 189. A tubular member 191 is provided which has one endsealed into one corner of the balloon 186 as shown in FIG. 20. Thetubular member 191 is provided with a lumen 192 which opens up into theinterior space 193 of the balloon. The sheets 187, 188 are formed of anon-elastomeric material of the type hereinbefore described. A Luerfitting 194 is connected into the free end of the tubular member 191 andis utilized for introducing a saline solution into the balloon 186 forinflating the same.

The graft or patch 182 can have a desired configuration, as for examplecircular as shown in FIG. 20. It is formed of a non-absorbable syntheticsurgical mesh, as for example from polypropylene manufactured by EthiconInc. As shown, the mesh patch 182 overlies the sheet 187.

The balloon assembly 182 with the patch 182 thereon can be rolled upinto a roll 196 as shown in FIG. 22 in which the patch or graft 182 isdisposed within the roll. The roll can be maintained in the rollconfiguration by sutures 197 wrapped about the same. The roll 196 canthen be introduced through a side trocar 146 and introduced into thedissected preperitoneal space 136 with the tubular member 191 extendingthrough the trocar 146 and having its Luer fitting 194 disposed outsideof the trocar. After the roll 196 has been introduced, the sutures 197can be removed and the balloon can be inflated by introducing a salinesolution through the fitting 194 by use of a syringe 199. Before thesaline solution is introduced to inflate the balloon, the roll 196 isproperly positioned so that when it is inflated and begins to unroll itwill unroll in the proper direction so that the graft or patch 182carried thereby is properly positioned as shown in FIG. 23. After theroll 196 has been completely unrolled, continued inflation of theballoon 186 moves the patch 182 so that it is pressed against theportion of the fascia through which the hernia has occurred as shown inFIG. 24. As soon as the graft 182 has been properly positioned, theballoon 186 is deflated. The trocar 146 is then removed, and thereafterthe balloon can be withdrawn through the opening in which the trocar waspresent. Thereafter, the gas utilized for insufflation can be permittedto discharge through another trocar so that the fascia 131 comes intoengagement with the peritoneum 132 with the large-area patch 182 held inplace therebetween. Thereafter, the trocars can be removed in the mannerhereinbefore described to complete the procedure.

Another embodiment of a balloon assembly for deploying a large-areapatch or graft through a trocar is shown in FIG. 25. The large-areagraft 201 shown in FIG. 25 is formed of a mesh material of the typehereinbefore described and has a generally oval-shaped configurationconforming to the general shape of the balloon 202 of the balloonassembly 203. The balloon 202 is constructed of a non-elastomericmaterial in the manner hereinbefore described. A tubular member 206 isprovided for inflating the balloon and has a Luer fitting 207 on thefree end thereof. Means is provided for retaining the mesh graft 201 onone side of the balloon and consists of plastic flaps 208 provided onopposite sides of the balloon 202, and secured thereto by a suitablemeans such as a heat seal along the broken line 209. The inner marginsof the flaps 208 are free and are adapted to receive the outer marginsof the graft 201 as shown particularly in FIG. 25.

The balloon 202 with the mesh graft 201 thereon can be rolled up into asubstantially cylindrical roll 211 by rolling the outer margins of theballoon inwardly on top of the mesh material to provide two rolls 211and 212 which are brought in adjacent to each other as shown in FIG. 26with the mesh graft 201 being wrapped up therewith. The two rolls 211and 212 can then be inserted into a tubular sheath 214. The sheath 214can then be introduced through a trocar in a manner hereinbeforedescribed and then pushed out of the sheath into the abdominal cavity.The balloon can then be inflated with a saline solution to cause the tworolls 211 and 212 to unroll in opposite directions and then for theballoon to inflate to move the patch 201 carried thereby into engagementwith the portion of the fascia having the hernia therein. Thereafter,the balloon can be deflated, the trocar removed, the balloon removed,and the dissected preperitoneal space deflated so that the large meshgraft 201 is disposed between the fascia and the peritoneum and isretained in position therebetween.

Another embodiment of a graft which can be utilized in connection withthe present invention is shown in FIG. 27. The patch or graft 216 isconstructed in a manner similar to the graft or patch 151 shown in FIGS.12 and 13, with the exception that it is constructed in a manner so thatit can be utilized with a direct hernia rather than an indirect inguinalhernia hereinbefore described. The graft 216 is formed of a sheet ofcircular mesh in the form of a disk 217 with a reinforcing central disk218 which has a barbed head 219 secured thereto. The barbed head 219 isformed of a biodegradable material such as polyglycolic acid. The meshgraft 216 can be folded over a deployment rod 221 and introduced into acylindrical sheath 222 (see FIG. 28) which is sized so that it can beintroduced through a conventional trocar, then deployed from the sheath22 by pushing on the deployment rod 221. After the graft 216 has beendeployed into the dissected preperitoneal space 136, it can bepositioned in an appropriate manner so that the barb 219 is positionedso that it is in alignment with the inguinal ring whereby upon deflationof the preperitoneal space 136, the barb 219 will extend through theinguinal ring to serve to retain the graft 201 firmly in place.

Another embodiment of a laparoscopic apparatus incorporating the presentinvention is laparoscopic apparatus. 231 as shown in FIGS. 29 through32. The laparoscopic apparatus 231 includes introducer sleeve or device32 identical to that hereinbefore described. It also includes atunneling shaft assembly 46 which is provided with a tunneling shaft orrod 47 and a proximal extremity 49 (see FIG. 32). In the previousembodiment of the laparoscopic apparatus, the tunneling shaft assemblyis provided with an olive-shaped or bullet-shaped tip 79 which wassecured to the distal extremity 49 of the tunneling shaft 47. In thepresent embodiment of the apparatus shown in FIGS. 29 through 32, theobturator tip 79a is detachably mounted on the distal extremity 49 ofthe tunneling rod 47. The proximal extremity of the tip 79a is providedwith a slot 236 which extends through one side of the proximal extremityinto the central portion of the proximal extremity of the tip 79a. Theslot 236 is adapted to receive the rounded extremity 237 provided on thedistal extremity 49 of the tunneling rod 47 (see FIG. 32). A removablesleeve 241 is provided as a part of a laparoscopic apparatus 231, and issimilar in many respects to the removable sleeve or sheath 106hereinbefore described. The removable sleeve 241 is formed of a suitablematerial such as Teflon as hereinbefore described and is provided with atubular member 242 which is provided with a relatively thin wall 243that has a weakened portion extending longitudinally thereof in the formof a slit 244 (see FIG. 31). The tubular member 242 is provided with aproximal extremity 246 and a distal extremity 247. The proximalextremity 246 has a thicker cross-section than the distal extremity 247,as shown in FIGS. 31 and 32. The proximal extremity 246 is provided witha recess 248 formed in the wall which is diametrically opposite the slit244 that serves as a relief region to permit the movable sleeve 241 tobe split apart when it is removed from the balloon.

The proximal extremity 246 is provided with wing-like members 251 and252 which extend diametrically therefrom, spaced 90° apart from the slit244. These outstretched wings. 251 and 252 serve to help the physicianorient the laparoscopic apparatus 231 as it is being utilized. Theproximal extremity 246 is also provided with a handle 256 which isformed integral therewith and which extends radially from the tubularmember 242. The handle 256 is provided with a finger hole 257 extendingtherethrough through which a finger can be inserted to facilitatepulling the removable sleeve 241 off of the balloon as described inconnection with the previous embodiment.

As shown in FIG. 33, the tip 79a is detachably mounted in the proximalextremity of the removable sleeve 241 so that the tip 79 can serve as asecond obturator during introduction of the laparoscopic apparatus 231as hereinbefore described. Means is provided for securing the detachabletip 79a to prevent it from becoming separated from the laparoscopicapparatus 231 and for permitting its withdrawal after the laparoscopicprocedure is being completed. As shown in FIGS. 33 and 34, such meansconsists of a flexible elongate element 261 in the form of a braidedstring formed of a suitable fabric such as Nylon, which has one end 262secured in a slot 263 provided on the distal extremity of the tip 79a bysuitable means such as an adhesive (not shown). The flexible elongateelement 261 extends from the distal extremity of the tip 79a in a recess264 opening through the external surfaces of the tip 79a. The proximalextremity of the flexible elongate element 261 can be secured directlyto the balloon 87 or, alternatively, it can extend through theperforated sleeve 101 provided in the balloon along the tunneling shaftso that it extends beyond the proximal extremity of the tunneling shaft.

The use of the laparoscopic apparatus 231 in performing a laparoscopicprocedure is substantially identical to that hereinbefore described withthe exception that when the removable sleeve 241 is removed from theballoon 87, the removable sleeve can be pushed forwardly to detach thetip 79a from the tunneling shaft 47. The removable sleeve 241 then canbe pulled rearwardly to separate it from the balloon along the slit 244.As soon as this occurs, the tip 79 becomes free of the sleeve and beginsto rotate in the direction of the arrow 266 shown in FIG. 34. When theballoon has been inflated and has performed its functions ashereinbefore described and it is now desired to remove the balloon 87,the balloon 87 can be withdrawn in the manner hereinbefore described,and since the tip 79a is tethered to the balloon 87 itself or flexibleelongate element 261 attached thereto extends out proximally of theballoon 87, the tip 79a is withdrawn or can be withdrawn with theballoon 87.

This laparoscopic apparatus 231 with its detachable obturator tip 79awill be useful in certain applications of the present invention. Withthe previous laparoscopic apparatus hereinbefore described, there is apossibility that when the obturator tip 79 is withdrawn, criticalstructures, as for example small arteries, may be inadvertently incisedbetween the tip 79 and the distal extremity of the tubular member 33 ofthe introducer device 32. This possibility is eliminated by having thedetachable tip 79a, which is withdrawn when the balloon is withdrawn.

Still another embodiment of the laparoscopic apparatus incorporating thepresent invention is shown in FIGS. 36, 37 and 38, in which thelaparoscopic apparatus 271 consists of a balloon 272 of the typehereinbefore described, which is provided with a perforated sleeve 273through which the tunneling rod 47 extends. The distal extremity 274 ofthe sleeve is closed by an end piece 276. The balloon 272 is wrapped inthe manner hereinbefore described around the tunneling shaft 247. Thetunneling shaft or rod 47 is not provided with a tunneling member orsecond obturator of the type hereinbefore described but its end isrounded as shown by providing a rounded tip 47a.

The wrapped balloon 272 is enclosed within a removable sleeve 281 whichis similar to those hereinbefore described. It is provided with atubular member 282 that has a weakened region in the form of a slit 283extending longitudinally the length thereof. The removable sleeve 281differs from those hereinbefore described in that rather than being openat the end as in previous embodiments, it is provided with a closed-end,bullet-shaped or olive-shaped tip 286. The slit 283 is provided with acurved portion 283a which extends through the bullet-shaped tip 286 sothat the sleeve can be peeled off of the balloon 272 in the mannerhereinbefore described by pulling on the handle 288 having a finger hole289 therein. During the time that the removable sleeve 281 is beingpeeled off or separated from the balloon 272, the balloon is held inplace by the tunneling rod 47 which engages the end 276 of theperforated sleeve 273. The balloon 272 after it is inflated can beseparated from the tunneling rod 47 by pulling on the balloon andcausing its distal extremity to lift up and to break apart at theperforations and peel away from the rounded extremities 47a of thetunneling shaft 47 as shown in FIG. 38. Continued pulling on the balloon272 will cause it to separate from the tunneling rod 47 so that theballoon 272 can be removed as hereinbefore described. Thus, it can beseen that there has been provided an embodiment of the laparoscopicapparatus of the present invention in which the need for an obturatorcarried by the distal extremity of the tunneling rod 47 has beeneliminated by providing the second obturator as a part of the removablesleeve 281. In all other respects, the operation and use of thelaparoscopic apparatus 271 is similar to that hereinbefore described.

From the foregoing it can be seen that there has been provided anapparatus and method for developing an anatomic space by the use of awrapped balloon which, as it is inflated, gradually unwraps to tend toform a plane to cause forces to be created perpendicular to the planefor pulling apart tissue along a natural plane to provide an anatomicspace, thereby providing a dissection in the weakest plane creating amore natural, less traumatic and bloodless region in which to performvarious medical procedures. Such anatomic spaces can be created invarious parts of the human body, for example in the preperitoneal areato provide a space anterior to the peritoneum for hernia repair and forvaricocele dissection. Spaces can also be developed lateral to theperitoneum and spaces posterior to the peritoneum for performing medicalprocedures such as a sympathectomy and a lymph node dissection.

As hereinbefore explained, the apparatus and method is particularlyappropriate for performing laparoscopic hernia repair, permitting theuse of grafts and patches which can be used for direct and indirecthernias with minimal pain to the patient and with the patient being ableto return to work within a few days.

Another embodiment of a laparoscopic apparatus 301 incorporating thepresent invention is shown in FIGS. 39-48. The laparoscopic apparatus301 can also be described as an assembly in the form of a surgicaldissector with a cannula which serves as a hand manipulated surgicalinstrument that can be used during general surgical laparoscopicprocedures to dissect the layers of fascia between the skin and theperitoneum as described in conjunction with the previously disclosedembodiments of the invention. The laparoscopic apparatus 301 consists ofa cannula 302 with a tunneling device 303 mounted therein. The tunnelingdevice 303 or guide rod 306 consists of a blunt obturator and anintroducer member 307. The laparoscopic apparatus also includes a skinseal assembly 311, a balloon assembly 312 and a balloon cover assembly316 as shown particularly in FIGS. 39 and 40.

The cannula 302 consists of a cannula tube 321 formed of a rigid plastichaving proximal and distal extremities 322 and 323. A flow passage 324extends from the proximal extremity 322 to the distal extremity 323. Acannula housing or handle 326 is mounted on the proximal extremity bysuitable means such by molding it directly thereon. As disclosed incopending application, Ser. No. 07/968,201, filed on Oct. 29, 1992, thehandle 326 includes first and second valve members (not shown) in whichone valve member serves as a duck-bill valve and the other valve memberserves as a circular instrument or tool seal. The housing is providedwith a Luer-type fitting 327 which is in communication with the interiorof the housing outside of the duck-bill valve and is in communicationwith the passage 324 in the cannula tube 321.

As described in said copending application, Ser. No. 07/968,201, filedon Oct. 29, 1992, the cannula 302 is adapted to receive the tunnelingdevice or blunt obturator device 303 which is generally of the typedescribed hereinbefore in the present application. This device 303consists of the blunt obturator 306 having a blunt tip 331 which isgenerally olive-shaped as shown (see FIG. 41) and is formed of asuitable material such as plastic. The olive-shaped tip 331 is molded onthe distal extremity 332 of a rod or a shaft 333 formed of a suitablematerial such as stainless steel. The blunt tip 331 is sized so that itsoutside diameter is slightly less than the inside diameter of thecannula tube 321. The proximal extremity 334 of the rod or shaft 333 hasmounted thereon a handle part 336 of a handle assembly 337 whichincludes a second handle part 338. The handle parts 336 and 338 areadapted to mate with each other and are detachably connected in a mannerdescribed in copending application, Ser. No. 07/968,201, filed on Oct.21, 1992 by the use of latch means (not shown) adapted to be actuated byspring-operated latch members 339 disposed on opposite sides of thehandle part 336 and adapted to be engaged by the fingers of the handholding the handle assembly 337. The second handle part 338 forms a partof the introducer device 307 and is mounted on the proximal extremity341 of an introducer member 342 formed of a suitable material such asplastic. The introducer member 342 is provided with a distal extremity343 and has a bore 344 extending from the proximal extremity to thedistal extremity through an end surface 346 (see FIG. 41) which isinclined at a suitable angle, as for example approximately 45°proximally from the horizontal axis for the bore 344. The bore 344 issized so it can slidably receive the shaft 333.

The handle part 338 is provided with hatch means (not shown) which isadapted to releasably connect the handle part 338 to the cannula housing326 and includes latch members 349 disposed on opposite sides of thehandle part 338 adapted to be engaged by the fingers of the hand holdingthe handle assembly 337 to permit the handle part 338 to be separatedfrom the cannula housing 326.

The skin seal assembly 311 generally can be of the type described incopending application, Ser. No. 08/124,333, filed on Sep. 20, 1993 andas described therein consists of a screw body 350 formed of a suitablematerial such as plastic having a helical thread 351 and a scallopedflange 352. A resilient insert 353 is disposed in the screw body 351 andis formed of a suitable resilient material such as silicone. The insert353 is provided with a bore 354 extending therethrough. A collet 357having slots 358 therein surrounds the insert 353 and is engaged by acollar 356 movable axially of the screw body 351 and is adapted to movethe collet to compress the insert 353 to move the insert between aretaining position for the cannula tube 321 extending through the bore354 to retain the cannula 302 in a desired longitudinal position withrespect to the skin seal assembly 311 and a releasing position in whichthe cannula 302 can be slidably moved longitudinally inwardly oroutwardly with respect to the skin seal 311. The collar 356 is providedwith an annular shoulder 359 having circumferentially spaced-apart slots360 therein which are used for a purpose hereinafter described. Asexplained in copending application Ser. No. 08/124,333, filed Sep. 20,1993 means is provided to restrain rotation of the collar 356 withrespect to the collet 357 and includes longitudinally extending keys 355spaced 180° apart.

The balloon assembly 312 consists of a balloon 361 formed of anon-elastomeric, medical grade plastic material of a suitable type suchas polyurethane. The balloon 361 can be characterized as having a mantaray shape when viewed in plan and is provided with a forwardly extendingrounded protuberance 362 which has a width substantially less than thatof the balloon 361. The balloon 361 consists of two sheets of materialwhich can be identified as a first or upper sheet 363 and a second orlower sheet 364 which have been die cut to the desired configurationwith their edges bonded together in a suitable manner such as by meansof a heat seal to form a balloon which has a generally flatconfiguration when deflated as shown in FIG. 40. The upper or outersurface of the first or upper sheet 363 has been toughened in areas 365as shown in FIG. 40 on the outwardly extending lobe portions 361a and361b for a purpose hereinafter described. The roughening can beaccomplished in any suitable manner such as by embossing the plasticmaterial with a pattern having raised portions therein.

Means is provided for inflating the balloon with a suitable medium, asfor example a liquid such as a saline solution and consists of aflexible tube 366 that extends into the balloon between the two sheets363 and 364 and forms a fluid-tight seal therewith. The interior of theballoon can be inflated and deflated by introduction of the fluidthrough the tube 366. The tube 366 is connected to a Y-adapter 367 whichhas one leg of the Y connected to a one-way valve 368 having a Luerfitting and the other leg connected to a tube 369 which is connected toa tapered fitting 371. A conventional pinch off clamp 372 is mounted onthe tube 369. The tube 366 is adapted to be releasably retained in theslots 360 of the shoulder 359.

Means is provided for removably securing the balloon 361 to thetunneling rod or shaft 306 and consists of an elongate tubular member orsleeve 376 which extends along the length of the balloon 361 and isdisposed on one side of the balloon 361 which can be called the top sidegenerally centrally of the balloon 361. The tubular member 376 isprovided with a passage 377 therein through which the tunneling or guiderod or shaft 333 extends. As hereinbefore explained, this tubular memberor sleeve 376 can be formed as a separate member which is bonded to thetop sheet 363 or alternatively can be formed integral with the top sheet363 with two heat seals being provided above and below to form thesleeve 376 with the passage 377 therein. The tubular member 376 can beprovided with spaced-apart elongate slits or perforations (not shown)extending along a line 378 in the tubular member 376 to facilitateseparation of the balloon from the tunneling rod 333 as hereinafterdescribed. With a such a construction it can be seen that the tunnelingrod or blunt dissector or obturator 306 overlies the balloon 361 foradvantageous features hereinafter described.

The balloon cover assembly 316 consists of a semi-rigid tube 381 formedof a suitable material such as plastic and is provided with proximal anddistal extremities 382 and 383. It is provided with a bore 384 (see FIG.42) which extends from the proximal extremity 382 to the distalextremity 383. The tube 381 is provided with a weakened region in theform of a partial slit 386 extending from the distal extremity 383 tothe proximal extremity 382 of the tube 381 on the bottom side of thetube 381 as viewed in FIG. 40 (also see FIG. 42). The tube 381 isprovided with a proximal end wall 387 which extends at a suitable angle,as for example 45° proximally with respect to the axis of the bore 384.

The balloon cover assembly 316 also includes a handle 391 which as showncan be formed as a separate part and is secured to the proximalextremity 382 of the tube 381 by a metal clip 392. The handle 391 isprovided with a tapered body 393 formed of a suitable material such asplastic which as shown in FIGS. 42 and 47 is open on the bottom side tomake accessible a longitudinally extending recess 394 which issemi-circular in cross-section. A pair of sideways extending wings 396are formed integral with the body 393 and lie in a plane which issubstantially coincident with the axis of the semi-circular recess 394.As shown, the wings 396 are disposed at the proximal extremity of thebody 393.

An upwardly extending fin 397 is formed on the body 393 substantiallyequidistant from the wings 396 in a direction generally perpendicular tothe plane in which the wings 396 lie. The fin 397 is relatively narrowand is provided with an upper surface 378 having notches 401 and 402therein. A vertically extending wall 406 is formed as a part of the fin397 and extends generally in a direction which is perpendicular to theplane of the wings 396. The wall 406 extends in a direction at rightangles to the fin 397 and has a gradually increasing thickness from thetop to the bottom ends of the wall (see FIG. 46). The body 393 isprovided with a pair of spaced-apart holes 407 spaced approximately 90°apart and 45° from each side of the fin 397. An elongate slot 408 isformed in the body 393 and is generally in alignment with the fin 397. Apair of camming slots 411 are provided on opposite sides of the body 393in the wings 396 adjacent the distal extremities of the wings adjacentthe body. The camming slots 411 are provided with inclined cammingsurfaces 412.

The body 393 is provided with a pair of diametrically disposedprotrusions 413 which extend into the recess 394 and which are adaptedto seat in a pair of diametrically opposed holes 414 provided in thedistal extremity of the introducer member 342.

The balloon cover assembly 316 also includes a clamping member 416 whichis provided with a central body 417 and a pair of downwardly extendinglegs 418 and 419 (see FIG. 43) which extend downwardly into the cammingslots 411. As shown, the central body 417 is disposed just distal of thefin 397 and is provided with semi-circular guides 421 formed integralwith the central body 417 and disposed on opposite sides of the fin 397in a fulcrum region which is just slightly above the point ofcommencement of the legs 418 and 419. The central body 417 is providedwith longitudinally extending reinforcing ribs 422 (see FIGS. 43 and45). It is also provided with a proximally extending latch portion 426which extends generally at right angles to the central body 417. Thelatch portion 426 is provided with a centrally disposed slot 427extending substantially the entire length thereof which receives theupper extremity of the fin 397 so that when the clamping member 416 issnapped into placed over the body 393, the latch portion 426 is disposedin the notch 401 and cannot clear the uppermost portion of the fin 397.The clamping member 416 as hereinafter described is adapted to be movedbetween positions in which it is disposed within the notch 401 oralternatively in the notch 402. Laterally extending rounded raisedportions 428 are provided on the central body 417 are adapted to beengaged by a finger of the hand when moving the clamping member 416 fromthe notch 401 to the notch 402.

Operation and use of the surgical balloon dissection apparatus 301 inperforming the method for developing an anatomic space for laparoscopichernia repair in connection with the apparatus shown in FIGS. 39-48 maynow be briefly described as follows in conjunction with the cartoonswhich are shown in FIGS. 49a through FIG. 49g. The surgeon in connectionwith the present method identifies the appropriate fascia layer to bedissected, either by direct visualization of the tissue and/or by manualpalpation. Let it be assumed that it is desired to perform a herniarepair on a patient 451 and that it is desired to create anextraperitoneal working space for performing the surgical repair. Thesurgeon makes a small incision 452 in the skin of the patient in theumbilicus or slightly lateral of the umbilicus. A retractor (not shown)can then be utilized to open up the incision and to move it laterally toeither side to locate the rectus muscles that run longitudinally of thebody of the patient on both sides of the umbilicus or navel. As soon asthe rectus sheath has been located, the incision is made in the rectussheath through the incision previously made midway between the two setsof the rectus muscles. The surgeon then grasps the laparoscopic orballoon dissection apparatus 301 by using a hand, as for example hisright hand as shown in FIG. 49A to grasp the handle assembly 337 tointroduce the blunt end 331 into the incision to engage the anteriorwall of the posterior rectus sheath. The balloon dissector 301 is thenadvanced longitudinally of the patient's body generally parallel to thetwo sets of rectus muscles as shown by the arrow 453 by using the rectussheath as a guide to pass the blunt tip 331 to cause separation oftissue and to pass over the arcuate line and transversalis fascia to thelevel of the symphysis pubis. This can be readily accomplished with theballoon dissector 301 because the balloon cover assembly 316 is latchedto and generally rigidly connected to the distal extremity of theintroducer member 342 of the introducer device 307 by having theprotrusions 413 provided on the tubular cover 381 seated within theholes 414 provided on the distal extremity of the introducer member 342.This provides a rigid assembly of the balloon dissector 301 so it can beoperated by the surgeon grasping the handle assembly 337 without theneed to have the physician grasp by the other hand an intermediate partof the balloon dissector to cause a desired manipulation and steering ofthe blunt tip 331 as the dissection of the tissue is accomplished as itis advanced.

The travel of the blunt tip 331 to the level of the symphysis pubis canbe readily ascertained by the surgeon who can use his hand to palpatethe abdominal region of the patient and thereby feel the blunt tip 331as it is advanced until the blunt tip 331 strikes the symphysis pubis.This can be readily ascertained by the right hand holding the handleassembly 337 feeling the impact of the tip 331 striking the symphysispubis 468 (see FIG. 50) which impact is communicated through the rigidstructure of the balloon dissector to the handle assembly 337 where itcan be felt by the hand of the surgeon. The balloon dissector 301 isthen advanced a small additional amount so that the blunt tip 331 dropsbelow the symphysis pubis 468. Thereafter, the balloon cover handle 391is engaged by the same right hand of the physician as shown in FIG. 49Band the thumb is used to engage the transverse rounded protrusions 428by moving the upper extremity of the clamping or latching member 416proximally to cause the latch portion 426 to move into engagement withthe notch 402 carried by the fin 397. As this is occurring, the legs 418and 419 carried by the central body 417 are moved from the positionshown in FIG. 42 to the position shown in FIG. 47 and in doing soengaging the camming surfaces 412 whereby the portions of the wings 396secured to the body 393 are cammed outwardly so that the protrusions 413are moved out of engagement with the holes 414. The direction ofmovement of the latch or clamping member 416 is indicated by the arrow454 in FIG. 49B. As soon as the handle 391 has been released, the handle391 is moved proximally with two fingers of the hand grasping the wings396 to pull them upwardly and proximally to cause the balloon coverassembly 316 to be removed. The balloon 361 is held in place by thetunneling shaft or rod 336 and exits through the slit 386 provided atthe bottom of the tubular cover 381 which serves as a tear away sheath.The balloon inflation tube 366 is retained in one of the slots 360 inthe shoulders 359 so that it does not become entangled in the wings 396as the balloon cover assembly 316 is removed. This exposes the balloon361 which has its side margins rolled inwardly in rolls 461 with onebeing rolled in a counterclockwise direction and the other being rolledin a clockwise direction so that they underlie the tunneling rod 333 asshown in FIG. 50. Also to provide optimum dissection as hereinafterdescribed before the rolling up occurs the forwardly extendingprotuberance 362 can be folded inwardly along a fold line 471 and thesidewardly extending lobe portions also can be folded inwardly alongfold lines 472. To inflate the balloon the pinch off clamp 372 is closedand a conventional 60 cc syringe 476 containing a saline solution isconnected to the one-way valve 368. The syringe 466 is then operated asshown by the arrow 477 to introduce the saline solution from the syringe476 366 the tubular member 366 and into the interior of the balloon 361to gradually inflate the same. The one-way check valve 368 ensures thatsaline solution cannot exit therefrom when the syringe 466 is removed.The syringe 476 after it has been emptied can be removed and refilledwith a saline solution which is introduced into the balloon in the samemanner to cause the side margins of the balloon 461 to unwrap inopposite directions as shown in FIG. 50 on opposite sides of thetunneling rod 333 until they become completely unwrapped. Typically, itmay take as many as approximately ten syringes of saline solution tocause the balloon 361 to completely unwrap and the move into an inflatedcondition as shown in FIG. 50. As the balloon is being filled andunwrapping, it continues to separate or dissect tissue overlying theperitoneum to provide an extraperitoneal working space between thetransversalis fascia and the rectus muscles.

As hereinbefore described, the balloon 361 in plan has an asymmetricmanta ray-like configuration to provide the desired optimumextraperitoneal working space for the hernia repair. The forwardlyextending protrusion 362 provided on the balloon 361 as it is inflateddissects distally from the distal extremity of the blunt tip 331 of theguide rod 333 serves to provide good dissection of tissue in the area ofCooper's ligaments and also to dissect laterally around the inguinalrings. By utilizing an asymmetric manta ray-like construction, it ispossible to provide a balloon 361 with its wide side margins or lobeportions 361a and 361b which when inflated to cause forward movement ofthe balloon 361 to dissect downwardly around the inguinal rings and towedge the balloon 361 in place. The forwardly extending protrusion 362as it is inflated dissects like a small balloon down to the Cooper'sligament. In this way, it is possible to obtain an extraperitonealworking space 478 which exposes all the desired anatomy at one timebefore moving off to the hernia sac and to do the final dissection forthe hernia repair. By providing such a large extraperitoneal workingspace it is unnecessary to manually advance the dissection. The balloonhas also been shaped to properly match the anatomy in which theprocedure is to be formed so as to reduce to a minimum the amount ofmanual dissection which may be needed. Since the balloon has aparticular shape and is formed of a non-elastomeric material, thedissection will occur in the desired locations which would notnecessarily be the case if the balloon were formed of an elastomericmaterial which generally would have a tendency to follow the path ofleast resistance. Additional assurance is provided for ensuring thatdissection will occur in the desired locations with the non-elastomericballoon of the present invention because the balloon is held in place bythe tunneling rod 333 underlying the symphysis pubis 468 as shown inFIG. 50. Also by providing roughened areas 365 these areas frictionallyengage overlying tissue so that the lobe portions 361a and 361b canserve as anchors to prevent displacement of the balloon 361 after theballoon 361 as it is being inflated.

After the amount of desired tissue dissection has taken place byinflation of the balloon 361 to provide the extraperitoneal workingspace, the balloon 361 is deflated by connecting the evacuation fitting371 into an evacuation port (not shown) of an operating room suctionsystem. The pinch clamp 372 is released to open the tube 369 to permitthe saline solution which had been introduced into the balloons 361 tobe sucked out to completely deflate the balloon from the inflatedcondition as shown in FIG. 49C.

After the balloon has been deflated, the tubular member 366 can begrasped by the fingers of the hand as shown and the deflated balloon 361pulled out through the incision 452 in the direction as shown by thearrow 481 in FIG. 49D. If necessary, the handle assembly 337 can be heldby the other hand. The balloon 361 as it is being pulled off has itssleeve 376 separates from the tunneling or guide rod 331 by breakingthrough the linear perforations lying along the line 378. The guide rod331 remains in place to preserve an easy entry into the extraperitonealspace which has been created. The balloon 361 can then be discarded.

After the balloon 361 has been removed, the left hand is used to graspthe lower second handle part 38 with the left hand while the right handengages the upper or first handle part 336 of the handle assembly 337.The fingers of the right hand then engage the latch members 339 onopposite sides by the fingers of the hand to release the first part 336from the second part 338 and to permit the left hand to move the secondpart 338 in the direction of the arrow 482 shown in FIG. 49E. The secondpart 338 carries with it the cannula 302 attached thereto and theintroducer device 307 which extends therethrough with the skin sealassembly 311 mounted on the cannula tube 321. This advancement over theguide rod 333 is continued until the distal extremity 343 of theintroducer member 342 has been advanced into the desired position. Assoon as this has been accomplished, the skin seal assembly 311 isslidably advanced on the cannula tube 321 until the skin seal approachesthe incision 452. The screw body 351 is then rotated by the fingers ofthe hand engaging the flange 352 and/or to the shoulder 359 to screw itinto the incision 452 and to form a gas tight skin seal with the skin ofthe patient. As soon as a good skin seal has been established, theintroducer device 307 is clamped in a fixed position with respect to theskin seal assembly 311 by pushing generally downwardly on the collar 356to engage the collet 357 to form a friction grip between the elastomericinsert 353 and the cannula tube 321.

After the cannula 302 is in a fixed in position, the blunt obturator 306can be removed along with the tunneling device or blunt obturator device303. This is accomplished merely by continuing to pull upwardly on thehandle part 336 with the hand in the direction indicated by the arrow.483 as shown in FIG. 49F. As this pulling motion continues, the blunttip 331 will engage the distal extremity 343 of the introducer member342 causing a withdrawal force to be applied to the second handle part338 to cause it to automatically release from the housing 326. Thispermits the blunt obturator device 303 to be removed through the cannulatube 321. This is possible because the blunt tip 331 has a diameterwhich can pass through the interior of the cannula tube 321 and throughthe valving provided in the housing 326. In withdrawing the guide rod333 carrying the obturator tip 331, it can be seen that it continues tobe guided by the introducer member 342 and thus will remain centeredwith respect to the cannula tube 321 to avoid any pinching action at thedistal end 323 of the cannula tube 321. As soon as the obturator tip 331strikes the introducer member 342, the handle part 338 is automaticallydisengaged from the cannula handle 326. The latch parts 349 aresubstantially buried within the second handle part 338 so they arerelatively inaccessible to the surgeon ensuring that he will operate thelatch parts 339 carried by the first handle 336 which helps to ensurethat the surgeon remove the handle parts 336 and 338 in two stages.

After this has been accomplished a source of gas such as carbon dioxideis connected to the stop cock valve 328. The stop cock valve 328 isopened to permit the carbon dioxide to inflate the dissectedextraperitoneal working space such as indicated by the dotted lines 476shown in FIG. 49G. The cannula 302 can then be utilized for introducinginstruments of various types into the dissected extraperitoneal workingspace. The inflation gas cannot escape because of the valving providedin the handle 326 of the cannula 302.

Additional cannulae can be introduced in various positions in theabdomen of the patient through which additional surgical instruments canbe introduced for performing the surgical procedure to be performed inthe extraperitoneal working space. The remainder of the hernia repairprocedure to be accomplished in the extraperitoneal working space issubstantially the same as hereinbefore described and therefore will notbe described in detail. By way of example, let it be assumed that ahernia sac has been formed in the patient, as for example by passingdown into the scrotum to form a typical indirect hernia. The hernia saccan be pulled out and ligated in a manner hereinbefore described.Thereafter, a piece of mesh as hereinbefore described can be introducedthrough another site and rolled out over the region through which thesac had previously passed. The mesh can then be stapled in place, as forexample along the Cooper's ligament. After the hernia repair has beencompleted, the extraperitoneal working space can be deflated by openingthe stop cock valve 328 and bleeding the CO₂ contained therein toatmosphere to permit the abdominal wall to return to its normal positionto help retain the mesh which has been placed in the desired position.

In connection with the formation of the extraperitoneal working spacewith the apparatus of the present invention, it has been found that itis desirable to have the guide rod 333 be in position in which itoverlies the balloon 361 because this helps to ensure that the balloondissection will occur in appropriate areas because the blunt tip 331underlying the symphysis pubis is retained in the desired position evenduring the time that the balloon is unrolling during inflation.Positioning the guide rod 333 in this manner, ensures that the balloon361 will roll out in the opposite directions from the rod and also tohelp to push the balloon downwardly during inflation.

In order to make the apparatus more user friendly, the parts which areto be moved for operation with respect to other parts have been colorcoded, as for example they can be colored black with the remaining partsbeing of another color, such as grey or white. Thus, the clamping orlatch member 416 is of a black color because it must be removed tounlatch the balloon cover assembly 316. Similarly, the collar 356 of theskin seal assembly 311 is of a black color because it must be moved toclamp the cannula 302 in a desired position. Similarly, the latch parts339 and 349 are of black color because they also must be moved toseparate the handle parts.

The wings 396 are provided on the balloon cover 316 in addition toserving as means to facilitate grasping of the balloon cover assembly316 when it is desired to remove the same, as serve to visually indicatethe plane in which the balloon 361 of the balloon dissection apparatus301 causes dissection. Generally this dissection plane is in a planewhich is parallel to the plane in which the wings 396 lie.

As hereinbefore explained, the introducer member 342 is provided with anobturator end surface or tip which is inclined at an angle in adirection away from the normal direction of insertion to inhibit anytendency that the tip might hang up on tissue as it is being advancedthrough the tissue during dissection.

The sizing of the blunt obturator tip 331 so it is smaller than theinner diameter of the cannula tube 321 helps to ensure that tissue willnot become entrapped or pinched between the tip 331 and the cannula tube321. In addition, as hereinbefore described, the obturator tip 331 istapered in both directions into a smaller dimension from the center toalso minimize the possibility of any tissue being entrapped between thetip 331 and the cannula tube 321 and thereby ensuring that a shearingaction will not occur.

In conjunction with the foregoing disclosure, it has been assumed thatthe balloon dissection apparatus hereinbefore described typically wouldbe disposed of after each use. In the event it is desired to economizeand it is desired to reutilize at least certain portions of the balloondissection apparatus after a use in a laparoscopic procedure, anotherembodiment of a balloon dilatation apparatus 501 incorporating thepresent invention is shown in FIGS. 51-55. As shown therein it consistsof a handle assembly 502 similar to the handle assembly 337 hereinbeforedescribed which includes a handle part 503 similar to the handle part336. Other parts of the balloon dissection apparatus 501 are not shownbecause they can be identical to those hereinbefore described. Thehandle part 503 is provided with two sections 506 and 507 which can befastened together in a suitable manner such as by ultrasonic bonding oran adhesive. Latch members 511 and 512 are provided on opposite sides ofthe handle part 503 and are provided with finger portions 513 that areadapted to be engaged by fingers of the hand which extend outwardlythrough recesses 514 in the sections 506 and 507. The latch members 511and 512 are each provided with a latch 516 which is yieldably urged inan outward direction by a yieldable spring member 517 engaging adownwardly depending lip 518 provided within the sections 506 and 507.The latch members 511 and 512 are pivotally mounted between the sections506 and 507 by pivot pins 519 formed integrally on the latch members 511and 512 and extending into bosses 521 provided in the sections 506 and107 which are formed of a suitable material such as plastic.

First and second inserts 526 and 527 formed of a suitable material suchas plastic are mounted in the sections 506 and 507. First and secondlatch members 531 and 532 formed of a suitable material such as metalare provided which are seated in recesses 533 and 534 provided in theinsets 526 and 527. The latch members 531 and 532 are generally U-shapedand are yieldably urged into engagement with each other to form anelongate slot 536 extending therethrough. Upstanding legs 538 formedintegral with the inserts 526 and 527 are provided in rectangular spaces539 in the inserts 526 and 527 so that the upper extremities of the legs538 can be flexed by movement of the latch members 531 and 532 as shownby dotted lines in FIG. 54.

A guide rod 541 is provided which is similar to the guide rod 333 withthe exception that its distal extremity 542 is also provided with anannular recess 533. The distal extremity 542 is provided with a chamfer544 and a pair of opposed flats 546 which extend through the chamfer544. The guide rod 541 extends through a hole 551 provided bysemicircular recesses formed in the sections 506 and 507 and by a hole552 formed by semicircular recesses in the inserts 526 and 527. A largerhole 553 formed by semicircular recesses in the inserts 526 and 527 of alarger diameter than the hole 552 is provided which receives apush-button 556 and extends through a hole 557 also formed bysemicircular recesses provided in the sections 506 and 507. Adish-shaped or concave recess 558 is provided in the sections 506 and507 and facilitates engaging the push-button 556 by a finger of thehand.

The pushbutton 556 is provided with a bore 561 which is sized so that itcan receive the distal extremity 542 of the guide rod 541. Thepushbutton is provided with sideways extending skirts 562 extending 180°with respect to each other and which are provided with distally andinwardly extending camming surfaces 563 which terminate at a tip 564that is generally V-shaped as shown in FIG. 51. The tip 564 is formed sothat it is adapted to enter into the slot 536 formed by the U-shapedmembers 531 and 532. Thus, when the pushbutton 556 is depressed, the tip564 will enter the slot 536 in a progressive manner to urge them apartso that the camming surfaces 563 carried thereby engage the U-shapedlatch members 531 and 532 in regions just above and below the guide rod541 so that the guide rod 541 is released by the U-shaped latch members531 and 532 permitting it to be pulled out of the handle part 503.Release of the guide rod 541 makes it possible to separate the guide rod541 from the remainder of the balloon dissection apparatus 501 so thatthe handle assembly 502 and the other parts carried thereby can beseparated from the guide rod. Thereafter, the guide rod 541, the balloon361 and the balloon cover assembly 316 can be disposed of. The otherparts of the apparatus can be reutilized after appropriatesterilization. In order to ensure that the other parts survivesterilization, it may be desirable to form the plastic reusable parts ofa suitable plastic such as a polysulfone.

In connection with the foregoing, it can be seen that by making minorchanges in the construction it is possible to save a great number ofparts of the balloon dissection apparatus for reuse after sterilization.Only the parts which are most difficult to clean are disposed of after aone-time use.

From the foregoing it can be seen that there has been provided anapparatus and method which is particularly suitable for developing ananatomic space such as an extraperitoneal working space between theabdominal wall and the peritoneum by dissecting tissue with the use of anon-elastomeric balloon. The balloon dissection apparatus has manyfeatures facilitating its use in developing such an anatomic space andfor particularly developing an extraperitoneal working space for herniarepair.

What is claimed is:
 1. A balloon assembly for use with a tunnelingmember comprising:a first sheet and a second sheet of a material whichis substantially inelastic within a predetermined range of inflationpressures, said first and second sheets each having outer margins, saidouter margins being bonded together to form a balloon having an enclosedspace; a sleeve on said balloon for receiving the tunneling member; anda tubular member extending into said ballon for introducing a ballooninflation medium into said enclosed space to inflate said balloon to apredetermined size and shape, as determined by said substantiallyinelastic material.
 2. The balloon assembly of claim 1 wherein saidballoon is generally oval-shaped when inflated.
 3. The balloon assemblyof claim 1 wherein said balloon is generally rectangular when inflated.4. The balloon assembly of claim 1 further comprising means on saidsleeve for releasably securing the tunneling member to said balloon. 5.The balloon assembly of claim 4 wherein said means on said sleeve forreleasably securing the tunneling member to said balloon comprises aweakened region extending longitudinally along said sleeve, saidweakened region being separable to permit said balloon to be separatedfrom the tunneling member.
 6. The balloon assembly of claim 5 whereinsaid weakened region is formed from a series of longitudinally spacedapart perforations.
 7. The balloon assembly of claim 1 wherein saidsleeve extends longitudinally along said balloon and is spacedsubstantially equidisant from said outer margins of said sheets.
 8. Theballoon assembly of claim 1 wherein each of the said outer margins ofsaid sheets is gathered toward a central axis of said balloon when saidballoon is deflated.
 9. The balloon assembly of claim 8 furthercomprising a balloon cover for retaining said balloon in a tightlygathered relationship about the tunneling member.
 10. The balloonassembly of claim 9 wherein said balloon cover is a relatively flexibletubular member which surrounds said balloon and which may be separatedfrom said balloon.
 11. The balloon assembly of claim 1 wherein saidballoon has a distally extending protrusion formed in a distal region ofsaid balloon.
 12. A balloon assembly as in claim 1 wherein said firstsheet has an upper surface and at least a portion of said upper surfaceis roughened.